Traditional hydraulic components with a valve unit for a hydraulic system regularly have a valve block and a valve piston. Here, the valve piston is moveably supported and guided respectively along a first bore in the valve block. The valve unit can regularly be admitted with pressurized hydraulic fluid via a corresponding port or pressure lines and is configured such that the valve piston is movable between a closed position and an open position.
Here, particularly when the valve unit is configured as a seated valve the bore is regularly formed as a blind hole in order to avoid the provision of unnecessary sealing elements. The disadvantage of this is the production process, as tight tolerances have to be maintained especially for the inner circumference of the bore. Thus, also configurations are known in which the bore first is formed continuously, wherein in this case corresponding sealing elements have to be provided or the bore is closed by a plug or the like later.
However, such sealing elements regularly result in hysteresis effects when opening and closing the valve unit. Here, such hysteresis effects may be undesired in particular with a pressure-dependent control of the valve unit, since they can displace the shifting point of the valve unit. On the other hand, the properties of the hysteresis change caused by the sealing elements can substantially change with an increasing wear of the sealing elements, what in particular with a very accurate control of the valve unit can lead to problems in that the shifting operation either is too late or too early.
Moreover, with the corresponding valve units there regularly result leakages through the end openings of the bore. These can hardly be avoided even by employing sealing elements, since the sealing properties of the sealing elements deteriorate with their wear, wherein with an increasing age of the sealing elements increased leakage effects occur. Such leakages regularly result in a contamination of members that are provided in the region of the hydraulic component with hydraulic fluid. Further, the leakage results in an undesired consumption of hydraulic fluid. Accordingly, it is required to clean the corresponding members, to replace or renew, respectively, sealing elements of the valve unit, and to refill hydraulic fluid in the hydraulic system. All of this is associated i.e., with a high time and cost expenditure and must be avoided.